This invention relates to a printing apparatus for printing a variety of information such as images and characters on a recording medium, such as a card. More particularly, this invention relates to a printing apparatus that are capable of switching printing methods according to characteristics of a recording medium or information for printing a variety of information.
Conventionally, a thermal transfer printing apparatus has been used to record a desired image or a character on a card recording medium such as a credit card, a cash card, a license card or an ID card by thermally transferring with a thermal head via a thermal transfer film. As an example, in Japanese Patent Publication (TOKKAI) No. 09-131930, a printing apparatus using a direct transfer method has been disclosed. The apparatus directly transfers an image and a character to a recording medium via a thermal transfer film. This method has an advantage of attaining a high quality image due to thermal sublimate ink. However, the recording medium needs to have a receptive layer on its printing surface to receive the ink. Therefore, only limited recording medium can be used, or the receptive layer needs to be formed on the surface of the recording medium.
Generally, a card made of a polyvinyl chloride (known as a PVC card) has been widely used as the recording medium that can receive the thermal sublimate ink. However, since the PVC card generates toxic substances when burned, recently it has been tried to switch to a card made of a polyethylene terephthalate (also known as a PET card).
Furthermore, in recent years, a new type of card media such as an IC card, which embeds an IC chip or antenna inside, has been used in a variety of fields. Because of the embedded elements, this type of card has an uneven surface, resulting in a printing problem.
In Japanese Patent Publication (TOKKAI) No. 08-332742, a printing apparatus using an indirect transfer technology, in which an image is transferred to an intermediate transfer medium after the image is transferred to a final recording medium, has been disclosed to solve the above problem. According to this method, it is possible to overcome the problems such as limited recording medium related to the receptive layer or the issue of printing on an uneven surface of the recording medium. Furthermore, this method makes it easier to print an image on an entire surface of the card medium as opposed to the direct transfer method.
However, in the intermediate transfer method, a running cost tends to be higher than that of the direct transfer method because of the intermediate transfer medium. Also, it takes longer time to finish printing. Furthermore, in terms of a card design, there are many cases where a front side needs to be printed on a whole area while only limited area such as precautions for card use is needed to print on a backside. Thus, there are merits and demerits for both printing methods. Therefore, it is possible to reduce a running cost by selecting a method most appropriate to a recording medium if a printing apparatus can switch between the direct transfer method and the indirect transfer method to print an image on a recording medium depending on an objective of printing. It is expected that such a printing apparatus will be used more widely in the future.
However, a printing apparatus that can apply the two printing methods requires a complex printing process, resulting in an increase in processing errors of the printing process.
An object of the present invention is to provide a printing apparatus that can switch between the direct transfer method and the indirect transfer method for printing and can reduce problems associated with the printing process.
Another object of the present invention is to provide a printing apparatus that reduces mechanical errors and failures inside of the printing apparatus while improving printing capacity such as a processing time or throughput time per specific number of the media.
Further objects and advantages of the invention will be apparent from the following description of the invention.
To attain the objectives, in the first aspect of the present invention, an printing apparatus is equipped with a recording medium transport device for transporting a recording medium supplied from a supply portion along a transport path; at least one printing device arranged on the transport path of the recording medium transport device for selectively forming an image on the recording medium and an intermediate transfer medium for temporarily holding the image at a predetermined image forming position; a transfer device arranged on the transport path of the recording medium transport device for transferring the image formed on the intermediate transfer medium on the recording medium; a mode setting device for selecting a mode between the first mode in which the printing device forms the image on the recording medium and the second mode in which the printing device forms the image on the intermediate transfer medium; and an intermediate transfer medium moving device for advancing and retracting the intermediate transfer medium between the image forming position and a retracted position according to the first mode and the second mode selected by the mode setting device.
The recording medium transport device transports the recording medium from the supply portion along the transport path. At least one printing device and the transfer device are arranged on the transport path in the recording medium transport device. When the first mode is set by the mode setting device to form an image on the recording medium, the printing device forms the image on the recording medium at the predetermined image forming position. When the second mode is selected to form an image on the intermediate transfer medium that temporarily holds the image, the printing device forms the image on the recording medium, and the image formed on the intermediate transfer medium by the printing device is transferred to the recording medium by the transfer device. The intermediate transfer medium advancing device advances the intermediate transfer medium between the image forming position and the retracted position according to the first and the second modes set by the mode setting device. According to this aspect, images are formed on the recording medium by the printing device based on the mode. Because the images formed on the intermediate transfer medium by the printing device are transferred to the recording medium by the transfer device, it is possible to switch between the direct transfer method and the indirect transfer method when printing the recording medium. Also, it is possible for the intermediate transfer medium moving device to retract the intermediate transfer medium to the retracted position according to the mode to make one transfer device idle when the other transfer device is in use thereby decreasing a problem associated with printing and improving the printing performance.
In that case, the intermediate transfer medium moving device may move the intermediate transfer medium to the retracted position when the mode setting device selects the first mode, or may move the intermediate transfer medium to the image forming position when the mode setting device selects the second mode. The intermediate transfer medium moving means includes the first platen capable of being arranged opposite to the printing device, and the intermediate transfer medium contacts an outer circumference thereof. The intermediate transfer medium moving means also includes the second platen capable of being arranged adjacent to the first platen and opposite to the printing device. One of the first and the second platens may be arranged opposite to the printing device, or the intermediate transfer medium may be detachable from the outer circumference of the platen arranged opposite to the printing device.
Also, to attain the aforementioned objectives, in the second aspect of the invention, a printing method includes the steps of transporting a recording medium and an intermediate transfer medium for holding an image temporarily to an image forming position; selectively forming an image on the recording medium and the intermediate transfer medium at the image forming position; transporting the recording medium to an image transfer position; and transferring the image formed on the intermediate transfer medium to the recording medium at the image transfer position. When forming the image on the recording medium at the image forming position, it is prohibited to form the image on the intermediate transfer medium.
According to this aspect, the printing apparatus transports the recording medium and intermediate transfer medium that holds the image temporarily to the image forming position and selectively forms the image on the recording medium and the intermediate transfer medium at the image forming position. When forming the image on the recording medium at the image forming position, it is prohibited to from the image on the intermediate transfer medium. The recording medium is transported to the image forming position, and the image formed on the intermediate transfer medium is transferred to the recording medium at the image transfer position. In this case, the intermediate transfer medium is separated from the image forming position so that it is prohibited to from the image on the intermediate transfer medium. In such a case, when the mode of forming the image on the recording medium is set, it is acceptable to either prohibit the image forming on the intermediate transfer medium or to separate the intermediate transfer medium from the image forming position.
Further objects and advantages of the invention will be apparent from the following description of the invention.